Microbes and Disease (original) (raw)

Last Updated : 23 Jul, 2025

**Microbes vs. diseases is an important point that should be known to every common man. Microbe commonly refers to any living entity except a virus, that is not visible to the naked eye. Microbes also called microorganisms basically can be of two types — harmful and beneficial.

The harmful bacteria are called pathogens. Microbes cause various diseases. Various preventive measures are to be taken to remain disease-free. Let us understand in detail about microbes and the diseases caused by them.

Table of Content

• Microbes and Diseases
• Types of Microbes and Diseases Caused by Them
• Mode of Transmission of the Disease
• Prevention of Diseases
• 10 Diseases Caused by Microorganisms and Their Symptoms
• Comparison Between Human Diseases and Pathogens

Microbes and Diseases

Several diseases are caused by microbes. These harmful microorganisms are called pathogens. They are one of the main causal agents of infectious diseases such as viral fever, flu in animals, birds, etc, measles, and many more. Strong evidences are found which show that microbes may contribute to many non-infectious chronic diseases for example some forms of cancer, coronary heart disease, etc. Various types of diseases are caused by different types of microorganisms. Different types of bacteria, viruses, mycoplasma, etc. are considered in the category of microbes.

Types of Microbes and Diseases Caused by Them

Various types of bacteria, viruses, fungi, algae, protozoa, mycoplasma, etc are considered in the category of microbes. These microbes can cause fatal diseases in humans, birds, animals and plants, etc. Given below is the table of diseases caused by microorganisms:

**Bacteria

All bacteria are not disease-causing bacteria. The harmful bacteria that infect an organism produces toxins. These toxins lead to diseases. Anthrax, cholera, etc are caused by bacteria. These bacteria can be killed by antibiotics.

**Viruses

Viruses can be observed only using an electron microscope. They remain inactive outside a living cell. As they enter the host body, they take over the entire cellular machinery of the host organism. They are not killed easily using any medicines. Measles, mumps, common cold, and smallpox are some diseases caused by viruses.

**Protozoa

Protozoa refers to the unicellular, eukaryotic, heterotrophic organisms. They are found either free-living or as parasites. They cause diseases like amoebic dysentery whose causal agent is amoeba. Other examples are malaria, sleeping sickness, toxoplasmosis, balantidiasis, etc.

**Fungi

Fungi are eukaryotic organisms which means that their cells contain membrane-bound organelles and clearly defined nuclei. Fungi are found growing in damp, moist areas on the body in humans and lead to infections such as athlete’s foot, ringworm, etc. Different plant diseases caused by fungi are mildew, smuts, rusts, etc.

Mode of Transmission of the Disease

Transmission refers to the process by which a pathogen spreads from one host to another. There are different ways of transmission of diseases. The diseases may be directly transmitted from one person to another or through a bacterium, virus, protozoa, or fungi.

There are two different modes of transmission of diseases which are explained below:

• **Direct Transmission: This is the process when the pathogen is directly transmitted from an infected person.
• **Indirect Transmission: The process where the pathogens are not transmitted directly from the infected person but through vectors such as mosquitoes, ticks, flies, etc. is called indirect transmission.

**Also read: Diseases – Definition, Classification, Types and Causes

Prevention of Diseases

Following are some precautions that can be taken for the prevention of diseases from harmful microorganisms which can be fatal if not treated well.

• **Sharing of Personal Items Should be Prevented: Personal belongings should not be shared with anyone. This may include things like drinking glasses, combs, toothbrushes, handkerchiefs, etc. Microbes and diseases are interlinked with each other. A small mistake may lead to fatal consequences.
• **Hygienic Practices Should be Maintained: Washing your hands at proper intervals, especially before taking or cooking food, and touching your mouth or eyes is very important. Most of the diseases caused by microorganisms are the result of unhygienic practices.
• **Taking Vaccination Timely: Vaccination is very important as it will most of the time prevent the pathogen from causing infection even if it enters the host body. Diseases such as chickenpox, hepatitis A and hepatitis B, diphtheria, etc.
• **Cleanliness Should be Maintained during Food Preparation: The diseases caused by microorganisms spread through food because proper cleanliness is not maintained during its preparation. Thus hygienic practices should be followed during food preparation.
• **Injuries Should be Covered: If a person is injured then the wounds should be properly covered with bandage. This will stop the spread of infection and stop any new infection in the open wound as well.

10 Diseases Caused by Microorganisms and Their Symptoms

The following are some diseases caused by microbes along with their symptoms:

**Common Cold

• It is caused by a virus named Rhinovirus.
• **Symptoms: The symptoms of the common cold include cough, sore throat, runny nose, slight body aches, mild headache, a low-grade fever, etc.

**Chickenpox

• It is caused by a virus named Varicella zoster.
• **Symptoms: The main symptom is a rash that turns into itchy, fluid-filled blisters that turn into scabs later. The rash first appears on the chest, back, and face, and then spreads over the entire body. It is also found inside the mouth, eyelids, or genital area. ll of the blisters become scabs in approximately one week.

**Ringworm

• It is caused by a fungus named Trichophyton rubrum.
• **Symptoms: The symptoms of this disease often depend on which part of the body is infected by the fungus, but the common symptoms are itchy skin, red, scaly, and cracked skin, ring-shaped rash, hair loss, etc.

**Bubonic Plague

• It is caused by a bacterium named Yersinia pestis. This bacteria multiplies in a lymph node that is near the body part where the bacteria has entered the human body. The patient should be treated with proper antibiotics otherwise the bacteria can spread to other parts of the body.
• **Symptoms: The symptoms of this disease include headache, chills, fever, weakness, and one or more swollen, painful lymph nodes that are called buboes. This form results usually from the bite of an infected flea.

**Whooping Cough

• It is caused by a bacterium named Bordetella pertussis.
• **Symptoms: A runny nose, nasal congestion, fever, cough, and red and watery eyes are some mild symptoms. The symptoms worsen with time and lead to the accumulation of thick mucus inside the airways that causes uncontrollable coughing.

**German Measles

• This is caused by a virus named Rubella.
• **Symptoms: The symptoms include a pink or red rash that begins on the face and then spreads downward to the rest of the body, swollen and tender lymph nodes, runny or stuffy nose, mild fever, red eyes, headache, muscle pain, etc.

**Tuberculosis

• This is caused by a bacterium named Mycobacterium tuberculosis.
• **Symptoms: They include cough, fever, chills, chest pain, weight loss, loss of appetite, tiredness, pain with breathing or coughing, night sweats, etc.

**Athletes’ Foot

• It is caused due to a fungus named Trichophyton mentagrophytes.
• **Symptoms: They include scaly, peeling, or cracked skin between the toes, burning or stinging, itchiness, especially just after taking off shoes and socks, inflamed skin that might appear reddish, purplish, or grayish, depending on the infected person's skin color, blisters, dry, scaly skin on the bottom of the foot that extends up the side, etc.

**Malaria

• It is caused by a protozoan named Plasmodium falciparum.
• **Symptoms: Some of the symptoms include fever, chills, headache, diarrhea, pain in the abdomen, nausea and vomiting, joint pain or muscle, fatigue, rapid breathing, and rapid heart rate, etc.

**Anthrax

• It is caused by a bacterium named Bacillus anthracis. This causes skin and gastrointestinal (GI) infections that can be dangerous.
• **Symptoms: The symptoms may include skin sores, vomiting, and shock.

Comparison Between Human Diseases and Pathogens

The following is a comparison between human diseases and pathogens. From the table below the pathogens that cause diseases, particularly in humans can be understood:

Conclusion - Microbes Vs Disease

Thus, it can be concluded that microbes can lead to severe fatal diseases. Also, all microbes are not harmful. A larger percentage of them are useful. Only a very small percentage of microbes are harmful. Microbes are of different types and have different vectors that carry them to the host organism. The infections caused by them in many cases may lead to mass deaths. Thus preventive measures should be followed strictly so that the infection can be prevented.

A**lso Read:

• Disease causing Microorganisms in Animals and in Plants
• Means of the Spread of Diseases
• Where do Microorganisms Live?